The improved sailboat design (U.S Pat. No. 4,326,475, Apr. 27, 1982) has been built and tested in a "proof of principle" prototype. The size and complexity of this realization has prompted the smaller version at the other end of the size and complexity spectrum. Whereas the prototype weighs 1000 pounds, the deck has been reduced, and the number of lines and cables has been reduced. Furthermore, the relative sail area and usable deck space have been increased. The design is readily foldable and the sail configuration and control strategies are marked improvements on the earlier design.
The present invention relates to the sailboats in the form of multipontoon or multiple hull structures.
By way of background, attention is called to U.S. Pat. No. 4,326,475, Apr. 27, 1982 which forms the basis for the improvements herein described.
The improved sailboat described in the referenced patent was found to require improvements in the selected components. The following improvement needs have been identified during testing of the prototype design. The concept of steering the sailboat by relative rotation of the stern hulls relative to the bow hulls proved difficult due to friction in the mechanical device used to rotate the stern hulls. The jib and main sail configuration required many control lines (sheets). In addition, the mast in the center of the deck cluttered the deck area. Finally the design of the improved sailboat required connection of many cables and lines which led to a long setup and takedown time.
The object of the present invention is to provide a sailboat with the good features of the earlier patent design along with improvements to remedy the observed deficiencies in the earlier prototype.
A further objective is to provide a sailboat which can be folded and unfolded without extensive assembly tasks.
A still further objective is to provide a sailboat which can be quickly deployed yet constitutes a reliable and sturdy structure.
A still further objective is to provide a sailboat which provides the greatest sail area to weight ratio and associated high speed capabilities.
A still further objective is to provide a sailboat whose weight is easily handled by one person.
A still further objective is to provide a sailboat with maximum clean deck area per unit displacement.
A still further objective is to provide a sailboat capable of utilizing the counterbalancing weight of the helmsman to the fullest extent possible, yet assure the necessary controls are always within reach.
A still further objective is to provide a sailboat which is extremely trimmable, via the use of centerboards at the two bow vertices and the rudder behind the stern vertex.
A still further objective is to provide a sailboat whose hulls operate with a low drag under both displacement and planing modes.
A still further objective is to provide a sailboat which can be readily rolled on the beach, into and out of the water utilizing small wheels incorporated into the structure.
A still further objective is to provide a sailboat which utilizes a self buoyant closed foil rudder and an extended rudder support structure both to steer the boat as well as to change the hull orientation relative to the triangular deck for optimum sailing performance.
A still further objective is to provide a sailboat whose extended rudder structure can rotate about a horizontal axis to allow the rudder, whose buoyancy supports its weight, to follow the waves and not come out of the water, with possible attendent loss of control.
A still further objective is to provide a sailboat whose sails are constrained by a crossbar to remain approximately parallel under all sailing orientations thus assuring the maximum simplicity in sail control.
A still further objective is to provide a sailboat which has the capability to rotate the sails approximately 360 degrees, such that the sails can be used to the maximum lift/drag efficiency, even in downwind sailing.
A still further objective is to provide a sailboat whose sails' boom crossbar connection is used to both adjust sail orientation by horizontal translation as well as to steer the boat by rotation of the crossbar.
A still further objective is to provide a sailboat whose dual sail configuration naturally offsets the tendency of the wind to capsize the craft.
A still further objective is to provide a sailboat whose hull design has the minimum wavemaking drag under low speed displacement sailing and high stability and low drag under high speed planing conditions.
A still further objective is to provide a low drag closed foil rudder configuration with inherent self supporting buoyancy and elimination of tip vortex drag.
A still further objective is to provide a leading edge configuration on centerboards and rudder which reduce surface spray and associated drag losses.
A still further objective is &:o provide a sailboat with shock absorbers on each of the hulls to dampen fluttering under high speed sailing conditions and to also limit hull rotation about the horizontal axis avoiding potential hull "dig in" and pitch poling the craft.
Other objects are evident in the description that follows.
The foregoing objects are achieved, generally, in a sailboat that includes a rigid tetrahedral space frame that comprises three beams that form the sides of the deck triangle and two masts and a third mast support strut which are secured in close proximity to the vertices of the deck at one end and themselves at the top ends. The pontoons or hulls are positioned at the vertices of the triangle and secured to the space frame at said vertices.